Field
The disclosed technology relates generally to semiconductor devices, and more particularly to semiconductor devices such as field-effect transistor devices configured for biomolecule sensing. The disclosed technology also relates to methods of fabricating and using the same.
Description of the Related Technology
Prior art nanowires and FinFET-based multigate devices are interesting device architectures for biosensing applications. Such devices show a high sensitivity, since the binding of biological molecules at the surface thereof can significantly affect the conduction path in these devices, does influencing measurement results. They sense biomolecules at a surface (captured from a solution) by exposing the gate of the device to a solution comprising the charged biomolecules.
A FinFET device acts as a transducer, translating and amplifying the difference in charge to a difference in conductance. The gate often comprises antibodies which are able to bind with particular biomolecules. In order to increase the sensitivity, these devices are often operated in the sub-threshold regime by applying a voltage on a back gate. In the sub-threshold regime the current through the drain is exponentially dependent on the voltage of the gate and therefore in this region the sensitivity is increased.
So far, the use of nanowires, both silicon and non-silicon based, has been limited to label-free sensing of biomolecules. Nowadays, there is also an increasing need for techniques that can sequence DNA in a very quick and cheap way. Sequencing involves determining the order of the bases Adenine, Cytosine, Guanine and Thymine in a gene or on a chromosome. Typically optics-based sequencing methods are used. These methods, although considered to have a very high accuracy, are very expensive, and hence are to be avoided if possible. Single-molecule sequencing technologies, such as nano-pores, can potentially be used to sequence long strands of DNA without labels or amplification. The main challenge is to distinguish the different nucleobases, as typically the difference is very small and for that purpose the controllability and reproducibility of nanopores is key.
In view of these applications (DNA and protein sequencing and in general biomolecule sensing) there is a need for good biosensing devices, i.e. biosensing devices with good sensitivity, which are preferably inexpensive.